Conventionally, at the time of laser beam machining by a laser beam machine 101, it is necessary to cover the whole laser beam machine 101 including a machining table 103, on which a work W is placed, with a safety cabin 105, as shown in FIG. 4, from a viewpoint of safety of the operator and working environment. Especially, in EC countries, in order to acquire the “CE mark”, the measure for covering the laser beam machine with the safety cabin 105 is necessary and indispensable. It is considered that the similar tendency will also dominate the Japanese market.
Generally, in the laser beam machine 101 in which a carriage 109 for supporting the laser machining head 107 is single in FIG. 4, a separately disposed manipulator 111 has been used to unload a machined work W (product G in FIG. 4). For example, the manipulator 111 is able to travel freely in the back and forth direction (X-axis direction), and the manipulator 111 has a holding device 113 for holding the work W, provided thereon so as to be able to go freely up and down and to move freely right and left. As a result, the holding device 113 is disposed so as to be moved and positioned freely back and forth (X axis), right and left (Y axis), and up and down (Z axis).
In the laser beam machine 101 capable of carrying in and out the work W, as in the case where a shuttle table 115 is provided as a machining table 103 for placing the work W thereon, the machined work W and a skeleton are carried out at the same time while a new work W is machined.
When the above-described laser beam machine 101 is completely covered with the safety cabin 105, it is necessary to open or close a door 117 disposed on the side of the safety cabin, after the laser beam machining has been suspended, in view of the purpose of the safety cabin 105.
In the conventional laser beam machining system, needless to say, safety and being convenient are two sides of the system, and performing the laser beam machining with the laser beam machine 101 covered with the safety cabin 105 has many problems in speed-up and efficiency improvement. Moreover, the safety cabin 105 becomes a cause of a delay in labor saving from a viewpoint of the productivity and care with respect to a defect of the work W.
Moreover, in the case of the laser beam machine 101 comprising the shuttle table 115, there is a problem in that when the machined work W carried out on the shuttle table 115 is picked up by the manipulator 111 (takeout loader or unloader) in order to take it out from the skeleton, the work W is shifted, thereby finally, it may not be taken out.
On the other hand, there is a problem in that after the cutting process of the work W by means of the laser beam machining has been finished, when the machined work W is picked up by the manipulator 111, the work W may not be taken out due to inclination, depending on the shape of the work W.
Therefore, as shown in FIG. 6, the laser beam machining is suspended in the middle of the cutting process of the work W, slightly leaving the uncut portion N (unmachined portion), shown by a two-dot chain line, and the side of the cut portion C of the work W is picked up in the direction shown by an arrow, as shown in FIG. 7, by the holding device 113 of the manipulator 111, and thereafter, the remaining uncut portion N is cut by the laser beam machining. The machined work W is taken out by the manipulator 111, and accumulated in the product accumulation area, as shown in FIG. 4, and the accumulated machined works W (products G) are taken out by a forklift, and assorted manually.
In this case, when the work W is picked up by the manipulator 111 described above, in the middle of the cutting process and after the cutting process of the work, as shown in FIG. 5, it is necessary to suspend the laser beam machining to open and close the door 117 of the safety cabin 105. Accordingly, in other words, the time required for opening and closing the door 117 of the safety cabin 105 is the time that does not contribute to the productivity, since the laser beam machining cannot be performed during that time.
In detail, the above-described series of steps comprise steps of: (1) performing laser beam machining with respect to a work W halfway, (2) opening the door 117 of the safety cabin 105 (3) letting the manipulator 111 enter into the safety cabin 105 from the door 117, (4) closing the door 117 of the safety cabin 105, (5) picking up the work W by the manipulator 111, (6) performing laser beam machining with respect to the remaining portion of the work W, (7) taking out the machined work W by the manipulator 111, (8) opening the door 117 of the safety cabin 105, (9) moving the manipulator 111 from the door to the outside of the safety cabin 105, and (10) closing the door 117 of the safety cabin 105.
Incidentally, the whole processing time required for cutting one work W by the laser beam machining in the above manner was, for example, 30 seconds. The breakdown was such that pure laser beam machining time in the steps (1) and (6) was for example 12 seconds, and the pick-up time of the work W and the opening and closing time of the door 117 in other steps (2) to (5) and (7) to (10) were for example 18 seconds.
As described above, there is a problem in that the productivity decreases, since the time for suspending the laser beam machining becomes long, as the laser beam machining is performed within the safety cabin 105.